Optical Fiber Communications 4th Edition by Gerd Keiser

Exercise 8

An LED operating at 1300 nm injects 25 µ W of optical power into a fiber. If the attenuation between the LED and the photodetector is 40 dB and the photodetector quantum efficiency is 0.65, what is the probability that fewer than 5 electron-hole pairs will be generated at the detector in a 1-ns interval